Sony hack: FBI vows to hunt down North Korean cyber criminals

FBI says North Korea's actions are "outside the bounds of acceptable
state behaviour"

The US government formally accused North Korea of carrying out a devastating cyberattack on a Hollywood studio and vowed to impose "consequences" on the hermit state led by Kim Jong-un.

It was the first time the US has directly accused another country of such an attack on its soil. North Korea's UN mission denied involvement, but it has previously called the hacking of Sony Pictures Entertainment a "righteous deed" carried out by sympathisers abroad.

In a statement the FBI said it now had "enough information to conclude that the North Korean government is responsible for these actions." It vowed to hunt down the hackers and "identify, pursue, and impose costs and consequences on" them.

The bureau added: "North Korea's actions were intended to inflict significant harm on a US business and suppress the right of American citizens to express themselves. Such acts of intimidation fall outside the bounds of acceptable state behaviour. We are deeply concerned about the destructive nature of this attack."

The escalating confrontation between Washington and Pyongyang stems from the now defunct plan of Sony Pictures Entertainment to relase The Interview, a comedy about a CIA plot to assassinate Kim Jong-un, on Chrismas Day.

The malware was similar to that previously deployed by North Korea, containing the same lines of code and encryption algorithms.

There had also been communications between several IP addresses known to be associated with North Korea and IP addresses linked to the attack.

FBI agents also found similarities to a cyber attack in March of last year against South Korean banks, carried out by north Korea.

Experts said the malware may have been present in Sony's computer system for months, perhaps even years, during which time passwords and company secrets were stolen.

The virus was then set off on Nov 24 which crashes the studio's computer systems in minutes.

A skull appeared on every computer screens with the warning: "This is just the beginning, we've obtained all your internal data."

The hackers were believed to have gained initial access by stealing the passwords of a high level IT employee. One expert said that gave them "the keys to the building."

Lamar Bailey, of cyber security company Tripwire, said: "Given the complete and total breach of the Sony networks the attackers were present on network for months if not years. The number of compromised systems and malware needed to pull this off is astounding."

The crisis exposed the limited nature of US options against North Korea which has few links to the outside world. Its $50 billion economy produces few goods for export.

Financial sanctions are already in place in response to its nuclear weapons programme, but the US Treasury has so far directly sanctioned only 41 companies and 22 individuals.

One possible response is to urge companies providing North Korea's telephone and television services to close them down.

Jim Lewis, of the Center for Strategic and International Studies, said: "In concrete terms, there's not a heck of a lot they can do because one, North Korea doesn't have an economy, and two, we've already got every sanction known to man against them."

In its latest message, sent by email to Sony executives, the hackers warned against releasing the film "in any form." They said pulling it had been a "very wise" decision and they would "ensure the security of your data unless you make additional trouble."

The Motion Picture Association of America called the attack a "despicable, criminal act."